Where my serious mechanic br/o/s at? This is a long question but I'm only asking because google didn't tell me what I want to know.
I'm rebuilding the Ford 8.8 axle under my Wrangler after a catastrophic carrier failure. Basically I removed a lot of the carrier from the housing with a magnet. I'm replacing everything in it and got the new bearing races tapped in a while ago. I took the old pinion bearings and used a sanding drum on a Dremel to open up the I.D. so they'll slide on and off the pinion instead of pressing on, thus I can take them on and off quickly and use them to get the pinion depth set up. Now I bought a new set of Ford Racing 4.56 r&p's for this and a Ratech Pinion Depth tool to help get the depth set. I have the pinion held into place without a crush sleeve and the pinion nut tightened down enough to give some rotation resistance. The tool is placed against the end of the pinion head with the arm resting against the axle tube face. You then stick a caliper through the hole and measure the distance to the surface where the carrier bearing race goes. With a little arithmetic, you are supposed to be able to calculate the pinion depth very closely (within a few thousandths) and determine how much shimming, if any, is needed.
What I've run into is this.. I've got run-out in the pinion head. I have no idea if this is normal or acceptable and don't know whether I should proceed. I gently cleaned up the face of the pinion head with ultra fine sandpaper to make sure there were no high spots before putting it in. I placed the tool up tight against the face and began to take the measurements. I rotated the head numerous times and measured to make sure it was the same every time, what I found was that the measurements varied by at least .030" I repeated this several times to make sure and got the same result each time. In an attempt to see the run-out, I backed the nut off just enough to let the gear spin freely and then spun it by hand as fast as I could. Based on the shiny face, I could see a bit of side to side movement at the tips of the teeth, but don't see it anywhere but the face. It's almost as if the whole gear runs true but the face is not perfectly perpendicular. If that were the case it wouldn't have any effect on the performance of the gears.
Basically my question is this. Should this be considered a big red flag that indicates a possible problem with the gears? If not is there another way to easily determine the pinion depth, possibly based on the old gear? It was a different brand but had a .030" shim on it. If that won't work, do I just bite the bullet and move on with the install to the point where I can use marking compound to check the pattern and determine if the depth needs adjusted from there?
Brandon Wood
How foolish of me to think there were mechanics on Veeky Forums >what was left of the stock TeacLok carrier
Ian Morales
If someone on Veeky Forums was a serious mechanic they wouldn't answer you as the last thing you want to do after solving problems all day and answering questions is do it more, but for free
Christian Collins
Oh come on now, surely there are nice people here. Right? Nice people? On Veeky Forums? Fuck who am I kidding, you're right.
Logan Jones
bumbreaker is just a faggot anyway.
You'll probably have better luck posting to forums that have members who know their shit. I think ericthecarguy did a rebuild on an 8.8"... You might try on those forums. Or even the HAMB.
Tyler Harris
If I were you I would just call Currie or another rear end specialist on Monday morning. You aren't going to get good info from any forum because even people that build cars as hobbyists rarely build rear ends and haven't seen enough of them to know what to look for when there's an issue
Asher Edwards
>nobody can ever do this unless they're a professional!!!!!!11 >HOBBYISTS ARE STUPID!!!
See, it's this elitist attitude of yours which makes people think you're a faggot.
OP, buy a shop manual on ford diffs. The more specific the better. Or do as I said at There's still some old farts on the HAMB who would know how to troubleshoot your problem.
Dylan Williams
Nice, just pulled up his channel. Truth be told I'm not sure if I've ever watched a vid of his before but there are a lot for the 8.8 on his channel I'll have to watch I was kind of afraid of that. I did enough reading and research that I felt comfortable taking this project along so long as everything went according to plan. I may try to get in contact with a guy at my job. There are over 500 employees in our facility and he's one that I've never really talked to, only heard about, but I'm told one of his previous jobs was installing gears at a Ford dealership for 8 years. He did one for another coworker and I hear he's legit.
Julian Russell
I've rebuilt the rear end in the corvette but it was an entirely different animal than this
Try a jeep forum
Julian Harris
You don't seem to understand. Even a veteran Ford mechanic might not have the answer, rear end rebuilds aren't very common, and they might not even be done in house. No hobbyist is going to have a large enough sample size to know off the cuff what a specific issue is going to be caused by, whether it's common, or whether it's an issue at all. Currie and similar operations have built tens of thousands of rear ends and can give you worthwhile info in a 3 minute phone call. On the internet the best you can hope for is regurgitated info, but more likely someone will just talk out of their ass having no idea what they are talking about.
Caleb Scott
You went to waaay too much work. You just use the pinion shim from the old gear set. Works every time with FRPP gears. Usually works with everybody else's too but I haven't seen those nearly as often.
You may also want to look at specs and clearances on the 8.8 and check everything else.
a differential isn't black magic. It can only be so many different things before OP finds out what is wrong. Humans built it, and if you're not retarded, you may be able to fix it through basic troubleshooting.
Jose Bailey
No I mean it was this guy's job to rebuild the rear ends. Apparently there was a recall on one of the truck rear ends and he installed 3 or 4 new sets of gears nearly every day for several months straight.
Hudson Wright
I just set up a mag base and dial indicator, I can only detect about .0015" variation measuring the peaks of each tooth so I'm feeling better about the run-out issue. It looks like its just the face of the gear that's a little wonky. I put a new shim of the same thickness as the old one in (destroyed the old shim getting it apart) and if I average the depth measurements it falls about .010" from the calculated target depth. I'm going to leave it like that until I check the mesh with marking compound and see how the pattern looks
Gabriel Powell
I let the pinion fall where it falls without shims and let the teeth wear together. You get some nasty whine for a few days but it goes away after a while
Alexander Murphy
lol sounds like a plan. For real though, I had a local 4x4 shop re-gear the stock axle some years back. It screamed so loud the stereo and wind noise couldn't drown it out. 'It's alright, they do that for a little while' they said. I knew it was wrong but fuck it. A week later I brought it back to them with all the teeth chewed off. They warranties it and rebuilt it again. This time it screamed around 35 and 70 mph. 'We took pictures all through the setup, we know it's setup right' they said. 3 months later I brought it back to them with all the teeth chewed off. 'Well we will warranty it one more time but if it happens again there is something wrong with your axle'. Must have brought in the big guns to set it up that time because it was quiet and lasted quite a while until I stripped several teeth off while off roading and decided to swap in the 8.8
Robert Fisher
This. Mechanic here but I've never messed with that particular rear end. In fact aside from changing fluid, seals and axle bearings i dont do much with rear ends ever.
Charles Watson
>Ford 8.8 Bruh you're the one that chose shit parts, it's not our fucking problem you choose shit parts that break and you have to fix. We don't owe you anything dumb nigger
I just only measured backlash setting and gear paint to approximate if it was acceptable or not, I did not bother to measure runout, but I replaced it to the same ratio as was before, 3.73, and from all the instructions I gathered, you didn't need to calculate run out so long as the ratio were the same.
But I could be wrong.....
Now a year out I have some binding that's noticeable at low speed braking but other than no issues have cropped up. I changed fluid last month and the gears are still meshed the same with a nice even pattern on the ring teeth.
Joshua Cruz
you're a shit mechanic then. Go change some more oil, oil boy.
I am installing the same ratio as what came out of it, but instead of getting another TracLok carrier that will probably fail again (35x12.50 tires seem to do that when you're heavy on the pedal) I bit the bullet and bought an ARB locker for it. I measured the carrier shim stacks that came out of it and made new stacks to match, but when I put them in I discovered that it was sloppy loose so I had to add .020" on the left to get the slop out. It's just tight enough that I can get them in and out by hand right now. So far I've ended up moving about .035" from the right to the left side and the backlash is currently sitting at .012" right on the upper end of the tolerance. I'm about to go to bed but I threw some yellow marking compound on a few teeth just to see how close it is. This drive side (what I've read is the more important one to pay attention to on a new setup) isn't quite where it should be
Evan Walker
Forgot pic
Jonathan Evans
The coast side looks pretty good though. I'll have to read on it and play to find out what she needs
Logan Hernandez
Yep, that'd be High Toe Drive indicating that the pinion is too "shallow". IE too close to the differential and needs a thinner shim, while the ring gear is too far from the pinion gear and you need to shift the ring gear to the left as you look at it. For this you might try just swapping the differential shims left for right.
